1. Field of the Invention
The present invention relates to a method for controlling interference. More particularly, the present invention relates to a method for controlling interference between adjacent cells in a communication system in accordance with an Orthogonal Frequency Division Multiplexing Access (OFDMA) scheme.
2. Description of the Related Art
A communication system in an Orthogonal Frequency Division Multiplexing Access (OFDMA) scheme whose frequency reuse factor is 1 controls interference between adjacent cells by a sub-channel configuration different from adjacent cells for each cell.
However, according to the scheme, as a load is increased in the cell, the effect of the interference control is reduced. Further, in order for a terminal close to a boundary of cells including Carrier to Interference and Noise Ratio (CINR) to obtain a targeted value, when a base station in the corresponding cell increases transmission power, the interference between adjacent cells occurs. Thus, the performance of adjacent cells is degraded.
Therefore, in order to overcome performance degradation due to the co-channel interference affected by other cells at the boundary of cells in the communication system according to the OFDMA scheme, the communication system can use Fractional Frequency Reuse (FFR) that orthogonally divides all the sub-carriers into a plurality of sub-bands and then, properly arranges the sub-bands between cells that do not use some of the sub-bands in each cell, thereby making it possible to mitigate the co-channel interference between adjacent cells.
However, a problem exists in that an autonomy network configuration or a mobile base station environment that does not permit communication between base stations controlling each cell cannot use the frequency reuse scheme or the fractional frequency reuse scheme. In addition, even in a case of permitting communication between the base stations, it is difficult to improve the performance of the system while guaranteeing communication between terminals at the boundary of cells only by using the fractional frequency reuse without power control.
Therefore, a need exists for a method for controlling interference between adjacent cells in a communication system.